Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

Unreasonable Fear of Hypotension and High-Dose NTG – Part II

ResearchBlogging.org
 

Continuing from Part I to look at the results of the study of high-dose SL (SubLingual) NTG (NiTroGlycerin – GTN GlycerylTriNitrate in Commonwealth countries) by EMS for CHF (Congestive Heart Failure) that Peter Canning wrote about.[1]
 

For CHF, more NTG does not produce more of a drop in blood pressure.
 

If you disagree, provide evidence.

I tend to get anecdotes, with excuses, rather than any kind of evidence.

Anecdotes are often indications that the person telling the anecdote does not understand and is trying to make up for that lack of understanding with bravado.
 


 

Therefore, we will continue to look at the evidence.
 


Click on images to make them larger.
 

You can see that some patients did have large drops in systolic blood pressure with only a double dose of NTG. To clarify, I highlighted the large drops in red below.
 


 

Only six large drops in systolic blood pressure.

Three systolic blood pressures dropped below 100 mmHg.

The expected happened with these dramatic drops in blood pressure and cases of hypotension –

Nobody had any bad outcomes.

The patients recovered without any intervention, such as fluid bolus, epinephrine, or whatever other placebo might be suggested.

Placebo?

A treatment that does not do anything more than doing nothing (benign neglect) is a placebo.

All these patients needed was a paramedic smart enough to use benign neglect.

Anecdotalists give a lot of treatments, because they mistakenly feel that that their intervention improve outcomes. Where is their evidence? In their overactive imaginations.

Those drops with double doses of NTG are scary. How bad was the outcome with triple doses of NTG?
 


 

Again, I highlighted the single big drop – only one – only dropped to about 130 mmHg systolic – in red below.

I added green to highlight the increases in systolic blood pressure after triple dose NTG. There were plenty of increases in systolic blood pressures after double dose NTG, but there were so many increases that it would have made the graph more difficult to read.
 


 

Multiple dose NTG every 5 minutes was clearly safe in this study.

Multiple dose anecdotes about Oh, no! What if . . . ? – continue to be wrong.

Forget the anecdotes.

There is plenty of evidence of safety.

Footnotes:

[1] Safety of High Dose Nitro in CHF
StreetWatch: Notes of a Paramedic
August 29, 2013
Peter Canning
Article

[2] Prehospital High-dose Sublingual Nitroglycerin Rarely Causes Hypotension.
Clemency BM, Thompson JJ, Tundo GN, Lindstrom HA.
Prehosp Disaster Med. 2013 Aug 21:1-4. [Epub ahead of print]
PMID: 23962769 [PubMed – as supplied by publisher]

Clemency BM, Thompson JJ, Tundo GN, & Lindstrom HA (2013). Prehospital High-dose Sublingual Nitroglycerin Rarely Causes Hypotension. Prehospital and disaster medicine, 1-4 PMID: 23962769

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